The invention relates to a method and a system for irradiating objects with infrared radiation, in particular for the purpose of drying surface layers and/or fixing them in position.
For example, a known procedure for the serial lacquering of the surfaces of objects is to transport the objects through a lacquering chamber. This chamber contains a mist of lacquer droplets, which precipitate onto the surfaces of the objects. Subsequently the objects are transported into a drying chamber where the layer of lacquer is dried.
Particularly in the case of objects with irregularly shaped, complicated surfaces it is further known to employ industrial robots that are freely programmable; these can spray nearly uniformly thick layers of lacquer onto the relevant surface regions. By means of the industrial robots it is possible to reach even relatively inaccessible parts of the surface, for instance in the region of recesses, cavities, joints and the like. The industrial robots can also be used to lacquer only specified parts of the surface.
In the manufacture of automobiles industrial robots are similarly employed to seal cavities, for instance in the wheel cases of a chassis. The pasty or liquid sealing material is disposed on the surface of the cavity by means, for example, of a spray gun carried by the robot.
Drying or fixation of the above-mentioned materials, after they have been applied by the industrial robots, is customarily achieved by passage through a continuous furnace. The time taken for the objects to pass through the furnace is predetermined such that the desired drying or fixation of the applied materials is accomplished. These passage times typically amount to several minutes.
Another known method of drying or fixation is by passing the materials through chambers in which large-area infrared radiators are disposed, for example on the walls of the chamber. These infrared radiators are typically operated at surface temperatures below 1000 K.
In both the continuous furnaces and the radiation chambers, large areas of the surfaces of objects, or even the object as a whole, are unavoidably heated. Material disposed at places on the surface that are hidden and/or difficult to reach, therefore, as a rule can be dried or fixed only by heating the object at least in the region including these places. That is, drying or fixation occurs by thermal conduction. The heat thus transported must previously have entered the body of the object by way of its surface. Furthermore, it is impossible to begin to dry or fix the applied materials while the process of application is still underway at other places on the surface of the object.
One objective of the present invention is to disclose a method and a system for irradiating objects with infrared radiation that enable a rapidly acting irradiation even of sites that are hard to reach, as well as a spatially restricted irradiation of specified regions of the surface of the object to be irradiated. Another objective is to disclose a means of applying infrared radiation to target objects that is suitable for the method and/or system.